Nausea and vomiting are common side effects of certain pharmacologic interventions and of surgery. These side effects can result from mechanical stimulation of the gastrointestinal tract, from chemical stimulation of various receptors in the body, or from both. These effects are particularly bothersome after surgical procedures under general anesthesia. Despite intense and ongoing efforts in past decades to reduce the impact of the problem, complete success remains elusive. A study in 1999 found the overall incidence of postoperative nausea and vomiting remained at a level of 30%, and rose even higher in the subset of patients with two or more risk factors.i 
Patients' perception of the quality of their anesthetic experience is strongly affected by the incidence of post-operative nausea and vomiting (PONV).ii Patients have even shown a willingness to pay out of pocket to avoid the problem of PONV.iii There is also considerable economic impact on the facilities that treat these patients and may have to deal with additional staffing and overhead costs as a result of delayed patient discharge due to PONV.iv v 
Various patient specific factors are known to influence the risk of nausea and vomiting. Some of the relevant factors influencing the risk of PONV include:                Female gender        Age        Menstrual cycle        History of motion sickness        Previous history of PONV        Smoking status        Type of surgical procedure        Types of anesthetic agents used        
Nausea and vomiting can be triggered by the introduction into the body of chemical substances or drugs, whether via oral or parenteral routes. These substances then result in activation of receptors in the brain or the proximal small intestine.vi vii If these introduced substances are interpreted by the brain as foreign or noxious, nausea and or emesis may ensue, as the human body perceives these drugs to be ingested foreign substances, which must be expelled from the body.
Most therapies introduced in the last few decades to combat drug-related nausea are intended to act at the receptor level by blocking receptors commonly believed to be involved in the reflex mediating a triggering of the emetic response. These therapies have included antihistamines, anticholinergic drugs, drugs acting on dopamine receptors, 5-HT3 receptor blockers, and more recently, an NK-1 receptor blocker, aprepitant.
The proposed invention utilizes a multi-component compound in a novel way. Rather than block key receptors immediately prior to or at the time of exposure to noxious agents, or immediately after symptoms of nausea and vomiting have appeared, this approach involves a conditioning approach whereby several of the principal known receptors in the nausea and vomiting reflex are gradually de-sensitized over a period of 7 or more days prior to the patient being exposed to the noxious agent(s). This desensitization is hypothesized to occur in two ways:
1. Agents similar in chemical composition or class to the drugs commonly used during the perioperative period are given in sub-emetic doses during this conditioning phase so as to desensitize the receptor groups to subsequent stimulation when similar drugs are given during the perioperative period. This is possible since humans can become tolerant to noxious substances upon repeated exposure.
2. Sub-therapeutic doses of some of the intermediate neurotransmitters involved in the nausea-vomiting arc are given such that desensitization and a reduced response will occur.
Mechanism #1 is analogous to the presumed mechanism by which smokers are protected from the nausea inducing effects of some drugs. Smokers constantly expose the chemoreceptor areas of their nervous system to a diverse blend of noxious chemical substances, which are introduced by inhalation and through the mucous membranes. They frequently experience nausea when they first begin to smoke cigarettes if they imbibe too much or too quickly. After a time, the smoker's body becomes desensitized to this wide variety of noxious agents. This desensitization carries over if the patients are exposed to other extrinsic chemicals, such as anesthetic drugs administered at the time of surgery, which explains why smokers have a significantly lower risk of PONV than do non-smokers.viii ix x 
Further evidence that desensitization can be accomplished is seen with serotonergic drugs. Selective serotonin re-uptake inhibitors (SSRIs) are a commonly administered class of drugs given to treat depression and other disorders. The most common side effect of all SSRI drugs is nausea, which is not surprising since these drugs raise the serum level of serotonin, which is known to function as a neurotransmitter in the nausea and vomiting reflex. Patients report anecdotally, however, that the nausea typically goes away after the first week or two of treatment and can be avoided or minimized by increasing the dosage slowly at the onset of treatment. This was also seen, particularly in early studies with SSRIs, where it was observed that gradual upward titration of SSRI dosage could greatly reduce or eliminate nausea symptoms when SSRI therapy was initiated.xi 
By using the phased, gradual introduction of the emetic provoking drug, or an analog thereof, the reaction to the acute administration of the same or similar class drug may be reduced or eliminated. By exploiting these effects, this agent will have the potential to reduce the acute incidence of nausea and vomiting that results from a perioperative exposure.
The invention consists of a compound which contains agents designed to desensitize the subject, whether human or other animal, to a number of different drug classes, as well as non-specific agents designed to reduce the overall chemical sensitivity of the subject.